ABSTRACT
I. INTRODUCTION One of the important functions of the immune system is the discrimination between self and nonself, or perhaps better between danger and nondanger. Currently, such discrimination is thought to be made through a series of complicated and multistep interactions between various cells and components of the immune system. Immune cells sometimes erroneously establish an immune reaction towards self during conditions of apparent nondanger. If such immune reactions are so aberrantly and vigorously self-directed, they may inflict pathological damage on tissues. So-called autoimmune diseases are the consequence.
